CO2 Laser Chemical Vapor Deposition of Amorphous Silicon: Gas Phase Processes and Thin Film Properties

Abstract

AbstractCW CO2 laser CVD of a‐Si:H was performed in a parallel configuration of the substrate and a horizontal CO2 laser beam. During deposition in situ gas analysis was performed by sampling through an orifice in the substrate surface (Ts = 400 °C) using a molecular beam and mass spectrometry. Time resolved measurements revealed a start‐up period of several minutes. Its influence onto the a‐Si:H film quality was investigated with respect to the dark and photo conductivities, optical band gap, fermi level, hydrogen bonding in SiH and SiH2 groups, density of defects in the mobility gap, and Urbach energy.